The present invention relates to encapsulated calcium having increased bioavailability and to other encapsulated minerals and encapsulated vitamins for use as an ingredient for the fortification of foods. The present invention also relates to methods for making the encapsulated mineral and vitamin ingredients and to food products, such as yogurt and ready-to-eat cereals, containing it.
The fortification of foods with minerals such as calcium, iron, magnesium, zinc, and selenium or vitamins, such as vitamin C to achieve a Recommended Daily Allowance (RDA) generally results in textural, taste, odor, color, separation, or inactivation, problems in the foods. Processing problems may also occur due to the presence of large amounts of minerals or vitamins in food compositions. In the fortification of foods with calcium, the low solubility of many calcium compounds, particularly the ones which are the more economical to employ, leads to low absorption into the blood stream as well as difficulty in their incorporation into foods. Calcium compounds tend to impart a chalky, gritty mouthfeel, off-flavors, and undesirable browning or discoloration. In addition, the form of calcium or the interaction, reaction, or complexing of calcium with proteins or other food components, during storage, or during heating or cooking in the preparation of the food may hinder or substantially prevent its absorption into the bloodstream or produce undesirable side-products.
Calcium plays an important role in blood coagulation, nerve transmission, muscle contraction, and heart function. Protection against high blood pressure, colon cancer, and the degenerative bone disease known as osteoporosis have been attributed to calcium. Approximately one percent of the body""s calcium circulates in the blood and the rest is present in bones and teeth. The U.S. Recommended Daily Allowance (RDA) of calcium is 1000 mg for adults and children 12 or more years of age. The RDA for pregnant and lactating women is 1200 mg. However, the average calcium intake is only about one-third of the required daily allowance. If dietary sources of calcium do not provide sufficient amounts of calcium to the blood, calcium is depleted from the bones to compensate for the insufficient amounts. Age related bone loss and fracture rates in patients with osteoporosis may be reduced with high dietary intake of calcium.
The ability of different individuals to utilize the calcium in food may vary considerably. For example, a high protein diet may result in about 15% of the dietary calcium being absorbed. A low protein diet may result in only about 5% of the dietary calcium being absorbed. Phytic acid in cereal grains interferes with calcium absorption by forming insoluble calcium phytate in the intestine. Oxalates in foods, such as spinach and rhubarb, may similarly interfere with calcium absorption.
Other intestinal factors that influence the absorption of calcium include pH, the calcium:phosphorus ratio, the presence of free fatty acids which occurs when fat absorption is impaired, and the amount of vitamin D. Generally, the more alkaline the contents of the intestines, the less soluble are the calcium salts. Also, a high calcium:phosphorus ratio favors the formation of tricalcium phosphate rather than the more soluble, better absorbed forms. If either calcium or phosphorus is taken in excess, excretion of the other is increased. The optimal ratio is 1:1 when the intake of vitamin D is adequate. On the other hand, vitamin D promotes the absorption of calcium from the intestine.
Although milk has been a major source of calcium for infants and young children, many teenagers and adult Americans are consuming lesser amounts of it. The calcium content of milk and other beverages may be increased to facilitate meeting of the U.S. RDA for calcium.
For example, calcium enrichment or fortification of milk is disclosed in U.S. Pat. Nos. 2,871,123, 4,701,329, 4,840,814, and 4,851,243. In U.S. Pat. No. 2,871,123 calcium carbonate is used as a calcium source in the production of a canned calcium-enriched concentrated milk product for dilution to make infant formula. Carrageenan gum is used for suspension of the calcium carbonate. U.S. Pat. Nos. 4,701,329 and 4,851,243 disclose the production of calcium-enriched and phosphorus-enriched fortified milk by the addition of tri-basic calcium phosphate, carrageenan and guar gum to fresh milk, effecting hydration of the gums, and assuring uniform distribution of the added materials in the milk. U.S. Pat. No. 4,840,814, discloses the preparation of calcium-enriched milk or toned milk by adding a water soluble calcium salt of an organic acid to thermally sterilized milk or toned milk, and adjusting the pH value of the obtained mixture to 6.6 or above.
Beverages and beverage concentrates nutritionally supplemented with solubilized calcium are disclosed in U.S. Pat. Nos. 4,737,375 and 4,740,380. In U.S. Pat. No. 4,737,375 the beverages and concentrates are substantially free of a sugar alcohol and contain specified levels of total edible acids selected from mixtures of citric, malic and phosphoric acid. U.S. Pat. No. 4,740,380 discloses a clear, calcium-fortified aqueous acidic beverage. The beverage comprises an aqueous solution of an organic calcium compound such as calcium gluconate at a pH of about 4 and below wherein the calcium compound content does not exceed the solubility limit of the compound in water. An inorganic calcium salt can be used alone or in combination with an organic calcium compound to form an acidic beverage provided the pH is adjusted with an organic acid.
However, when incorporating calcium into liquids, the source of calcium, usually an inorganic salt in finely divided form, tends to settle out upon extended storage. Also, the use of soluble sources of calcium or even the use of suspended sources of calcium tends to result in off flavors, adverse appearance, and undesirable increases in viscosity. Generally, the more soluble the salt or the more finely divided it is so as to improve suspendability, the quicker or more easily its taste will be detected. Also, solubilization of the calcium increases the likelihood of it being complexed with or interacting with other components of the beverage or of other foods consumed with it. The complexation or interaction of the calcium may result in it being less susceptible to absorption into the blood.
U.S. Pat. No. 4,676,583 discloses the production of an aseptic calcium-enriched soy bean curd by adding a calcium hydroxide-sucrose complex as coagulant to the soy bean milk, sterilizing the resulting mixture by heating, adjusting the pH value of the sterilized product to weakly acidic, charging the sterilized product into a container under an aseptic condition and sealing the opening of the container. The calcium hydroxide-sucrose complex is coagulated with the soybean milk by heating. When the calcium hydroxide-sucrose complex used as coagulant is insufficient to provide the required extent of calcium enrichment, calcium lactate may be added in an aseptic atmosphere after the sterilization process at the time of pH adjustment.
Calcium compounds have been utilized in baked goods, such as crackers, as components of leavening agents, pH adjusters, yeast foods, and for their nutritive value. U.S. Pat. No. 4,196,226 discloses a leavening acid comprising alkali metal aluminum phosphate granules having a calcium rich outer surface for improving flow and dusting properties. The product may be used as a leavening acid in moist doughs, and liquid batters such as pancake batters. U.S. Pat. No. 4,678,672 to Dartey et al discloses the use of calcium and ammonium carbonates and bicarbonates in leavening systems for the production of reduced calorie crackers. Various emulsifiers are disclosed as replacements for fat. Magnesium and/or calcium carbonates are taught as acid-neutralizing constituents in British patent 335,214 for dough or flour compositions which contain persulphates and bromates. Calcium carbonate is disclosed as a bread improver in U.S. Pat. No. 2,970,915. It is also taught as a buffering agent for a liquid yeast brew in U.S. Pat. No. 3,490,916. The dough-up stage addition of calcium carbonate for its nutritive value in the production of reduced fat or no-added fat crackers, is disclosed in U.S. Pat. No. 5,108,764 to Craig. U.S. Pat. Nos. 4,859,473 and 5,066,466 to Arciszewski et al disclose the addition of calcium carbonate to the dough-up stage for its nutritive value in the production of low sodium crackers. U.S. Pat. No. 5,514,387 to Zimmerman et al discloses the use of an emulsifier system to substantially increase the calcium content of crackers and other baked goods without adversely affecting texture of the baked goods.
Calcium fortification of yogurt is disclosed in U.S. Pat. Nos. 4,784,871, 5,449,523, and 5,820,903. According to U.S. Pat. No.4,784,871 a calcium fortified yogurt is produced by adding an acid soluble calcium salt to fruit flavoring which is subsequently combined with a yogurt base. Sugar is added to the fruit to assist in the avoidance of lumping of calcium phosphate. The fruit is employed to solvate a portion and to suspend the balance of the insoluble calcium within the yogurt product. In the process of U.S. Pat. No. 5,449,523 chelating agents are added to avoid undesirable milk protein precipitation. Usage of such chelating agents, however, contribute an undesirable flavor to the yogurt at the high levels necessary to fortify to 1000 mg calcium. U.S. Pat. No. 5,820,903 discloses preparing a fermented dairy product, such as yogurt, fortified with calcium that is visually undetectable in the final product. The process involves the post fermentation addition of a source of insoluble calcium phosphate having a particle size of less than 150 microns. Sufficient amounts of calcium phosphate of the requisite particle size are added with minimal shear to the fermented dairy product to provide a total calcium content of a maximum of 1500 mg of calcium per 227 g of product. The calcium phosphate salt is admixed with a liquid carrier to form a slurry comprising about 30 to 40% calcium phosphate.
In U.S. Pat. No. 4,765,996 polished rice or barley is enriched with nutrients which are fixed in and on the grain by coating an oil/fat and/or a wax on the grains, coating the same with a hydrophilic emulsifier and further coating them with a starch-based coating agent.
Mineral and vitamin fortification of high fiber, ready-to-eat cereals with minerals such as calcium and iron, and vitamins such as the B vitamins is disclosed in International patent publication no. WO 99/34688, published Jul. 15, 1999. The cereals are fabricated from cooked cereal doughs containing high levels of soluble fiber supplied at least in part by inulin or other xcex22-1-fructofuranose materials.
As disclosed in International patent publication no. WO 99/34688, as well as in U.S. Pat. No. 4,871,574, inulin is known for use as a prebiotic, that is, a food material that is metabolized in the intestine by desirable bacteria such as bifidus and lactobacillus. The promotion of desirable intestinal flora, it is taught, is thought to be related to a variety of health benefits. The lowering of blood lipids by consumption of inulin is reported in Brighenti et al, xe2x80x9cOne Month Consumption of Ready-to-Eat Breakfast Cereal Containing Inulin Markedly Lowers Serum Lipids in Normolipidemic Men,xe2x80x9d Proceedings of 7th FENS European Nutrition Conference, Vienna, 1995. The use of inulin as a fat replacer in cookie cream fillings is disclosed in U.S. Pat. No. 5,939,127. Health benefits of inulin as well as its use as a fat replacer are reported in: a) xe2x80x9cInulin-A xe2x80x98Good-for-youxe2x80x99 Fat Replacer, Texture Modifier,xe2x80x9d Food Formulating, p 15 (February 1997), b) xe2x80x9cInnovate with Raftiline,xe2x80x9d published by Orafti Active Food Ingredients, Tienen Belgium, doc. B1-60, edited by P. Coussement (11/1196), and c) Silva, R. F., xe2x80x9cUse of Inulin as a Natural Texture Modifier,xe2x80x9d Cereal Foods World, American Assoc. of Cereal Chemists, vol. 41, no. 10, pp 792-794 (October 1996).
However, as disclosed in International patent publication no. WO 99/34688 fiber, especially insoluble fiber, may adversely affect selected mineral and vitamin absorption. Accordingly, the cereals are fortified with bioavailable sources of calcium and other minerals and vitamins. The mineral fortifiers may be incorporated into the cereal compositions directly, and vitamins are preferably topically applied.
Other food compositions which contain inulin and minerals or vitamins are disclosed in U.S. Pat. Nos. 5,952,033 and 5,972,415. The production of gelatinized cereal products which may be used as a pet food or breakfast cereal is disclosed in U.S. Pat. No. 5,952,033. A starch source, a protein source, a plant material which is a source of inulin, and water are heated to gelatinize the starch. The matrix making up the cereal product must be gelatinized to remove or destroy the sesquiterpene compounds present in the inulin-containing plant material to reduce bitter flavors and palatability problems. In making a simulated pet food, an emulsion is formed and additional ingredients such as sugars, salts, spices, and minerals may be added to the emulsion. The final product has the appearance and texture of meat. U.S. Pat. No. 5,972,415 discloses a nutritive composition based upon fibers which is prepared by mixing pea fibers and inulin in demineralized water at 65xc2x0 C. to 70xc2x0 C., subjecting the mixture to a colloid mill, then combining it with a pre-emulsion to form a mixture and subjecting the mixture to a colloid mill. The resulting emulsion is admixed with carbohydrates, a protein mixture, minerals and vitamins. The composition is then heat treated at 150xc2x0 C. and stored.
However, the processes of U.S. Pat. Nos. 5,952,033 and 5,972,415 employ substantial amounts of water, and do not prevent adverse interaction between the inulin and minerals. Also, the products obtained tend to be rubbery or creamy and are not easily grindable into fine particulate compositions or powders for incorporation into other foods.
The encapsulation of minerals and vitamins in plasticizable matrices is disclosed in International Patent Publication No. WO 98/18610 (published May 7, 1998) and International Patent Publication No. WO 99/48372 (published Sep. 30, 1999) each to van Lengerich. In the process of International Patent Publication No. WO 98/18610 the plasticizable matrix material, such as starch, is admixed with at least one plasticizer, such as water, and at least one release-rate controlling component under low shear mixing conditions to plasticize the plasticizable material without substantially destroying the at least one plasticizable material and to obtain a substantially homogeneous plasticized mass. The plasticizer content is substantially reduced and the temperature of the plasticized mass are substantially reduced prior to admixing the plasticized mass with the encapsulant to avoid substantial destruction of the encapsulant and to obtain a formable, extrudable mixture.
Production of an edible composition that has a chewable texture and has at least one encapsulated component is disclosed International Patent Publication No. WO 99/48372. A free-flowing mixture, such as ground cookies and a plasticizer such as oil and water are mixed with an encapsulant to obtain a formable dough or crumbly mass. The dough is shaped or formed into pieces or pellets and dried to a shelf-stable moisture content. The processing is conducted at a temperature sufficiently low so as to prevent thermal degradation of the encapsulant and pressures sufficiently high to enable the formation of coherent pieces. The encapsulant may be vitamins and minerals such as calcium, selenium, magnesium salts, available iron, and iron salts. Soluble or insoluble fiber may be included to control release of encapsulant. Hydrophobic components, it is disclosed may be employed to help prevent or delay penetration of water or gastric juice into the matrix by repelling water or aqueous acids thereby delaying release of the encapsulant into the surrounding media. The amount of active component or encapsulant which is incorporated into the products may be such so as to provide or deliver an effective amount of the active component at its intended location, such as the small intestine.
Encapsulation of components in a plasticizable matrix to achieve a plasticized mass or an extrudable consistency, using substantial amounts of a plasticizer such as water, generally results in a pliable, chewable, or rubbery texture in the plasticized composition. To achieve a solid, or readily grindable consistency would entail removal of the plasticizer.
Encapsulation of components in a grindable, glassy carbohydrate matrix is disclosed in U.S. Pat. Nos. 5,009,900 and 5,087,461 to Levine et al, and U.S. Pat. Nos. 5,972,404 and 6,004,594 each to van Lengerich. In U.S. Pat. Nos. 5,009,900 and 5,087,461 to Levine et al volatile and/or labile components, such as vitamins or flavoring components, are encapsulated in extruded glassy matrices comprising a water-soluble, chemically-modified starch having a dextrose equivalent not greater than about 2, a maltodextrin having a dextrose equivalent in the range of from about 5 to about 15, corn syrup solids or a polydextrose having a dextrose equivalent in the range of from about 21 to about 42, and a mono- or disaccharide. U.S. Pat. Nos. 5,972,404 and 6,004,594 disclose encapsulation of an emulsifier in a low molecular weight carbohydrate in powder form rather than in a conventional shortening component. Low molecular weight carbohydrates which may be employed are mono- or di-saccharides, maltodextrins having a dextrose equivalent (DE) in the range of about 4 to 20, and corn syrup solids or polydextrose having a dextrose equivalent in the range of about 21 to about 97. Lower concentrations of emulsifiers, it is disclosed, provide comparable emulsifier performance by virtue of enhanced dispersion of the emulsifier.
International Patent Publication No. WO 99/65336 to Clark et al (published Dec. 23, 1999 discloses that the use of encapsulants or coating agents to mask or reduce the disagreeable sensory characteristics associated with fortification so as to prevent interaction of the fortificants with the senses is not cost effective. Coating agents, it is disclosed are expensive and the encapsulation process can use spray drying or fluid bed granulating which requires high energy use. In the process of WO 99/65336, fortificant particles are agglomerated with a binding/masking agent and the particles are added to an edible composition, such as a ready-to-eat cereal. The agglomeration reduces the surface area, dispersibility and solubility of the fortificants such as calcium, zinc, iron or other transition metals, or vitamins.
In the present invention, the concentration of minerals and vitamins in foods is substantially increased to provide Recommended Daily Allowances (RDA) without adversely affecting color, texture, taste, odor, or other sensory characteristics of food compositions such as ready-to-eat cereals, and yogurt. The fortification of foods with minerals such as calcium, iron, magnesium, zinc, and selenium or vitamins, such as vitamin C to achieve a Recommended Daily Allowance (RDA) is achieved without processing, separation or activation problems in the foods. The encapsulated mineral and vitamin compositions of the present invention may be produced without substantial amounts of water, and without substantial adverse interaction between the encapsulant and the encapsulating matrix composition. The encapsulated products are non-rubbery and readily grindable into fine particulate compositions or powders for incorporation into or onto food compositions. In accordance with the methods of the present invention, an encapsulated product may be obtained by extrusion without the need for removal of substantial amounts of plasticizer, such as water, and without the need for plasticizing or gelatinizing starch.
In accordance with embodiments of the present invention, the fiber content of foods may be increased, and the palatability of minerals and vitamins is increased without adversely affecting mineral and vitamin absorption. In the fortification of foods with calcium, absorption of calcium into the blood stream is substantially enhanced by encapsulating matrix compositions of the present invention. Fortification of foods such as ready-to-eat cereals and yogurt with Recommended Daily Allowances (RDA) of calcium is obtained without imparting a chalky, gritty mouthfeel, off-flavors, and undesirable browning or discoloration. Adverse interaction, reaction, or complexing of calcium with proteins or other food components, during storage, or during heating or cooking in the preparation of the food so as to hinder or substantially prevent its absorption into the bloodstream or produce undesirable side-products are avoided with the methods and compositions of the present invention.
The present invention provides a non-rubbery, particulate, ground or powdered mineral and/or vitamin fortification ingredient which exhibits a smooth mouthfeel, and masks undesirable odor, off-flavors, and scratchy or excessively gritty texture attributes of the encapsulant. It may desirably provide a slight degree of sweetness, is readily dispersible in foods without discoloring the foods. The fortification ingredient increases the fiber content of foods without adversely affecting mineral and vitamin absorption, and provides a controlled release of the encapsulant.
The fortification ingredient may be produced by encapsulating a mineral, such as calcium, or a vitamin in a glassy matrix. An encapsulant component comprising at least one mineral or vitamin is admixed with an edible oil to obtain a slurry wherein the oil encapsulates the mineral or vitamin. The slurry is admixed with a melt comprising at least one molten glass-forming oligosaccharide matrix component, such as fructooligosaccharides or inulin, to obtain a molten blend. The molten blend is cooled to obtain a formable, pliable mass. The formable, pliable mass may be extruded and cut into pieces or pellets and cooled to obtain a grindable, glassy matrix which encapsulates the oil encapsulated mineral or vitamin. In embodiments of the invention, further size reduction of the cut pieces may be performed by grinding the glassy matrix into a fine powder. The grindable, non-rubbery fortification ingredient may be obtained without the need for starch gelatinization or substantial moisture reduction steps.
To increase load levels of the mineral or vitamin encapsulant in the fortification ingredient, an additional amount of the encapsulant component may be admixed with the glass-forming oligosaccharide matrix component. The oligosaccharide matrix component is heated in the presence of the additional encapsulant component to form the melt which is then combined with the oil slurried encapsulant component. In forming the melt, water may be admixed with the glass-forming oligosaccharide matrix component to at least partially dissolve or plasticize the glass-forming oligosaccharide matrix component. Heating of the glass-forming oligosaccharide matrix component in the presence of the water facilitates formation of the melt and reduces its viscosity for easier mixing with the oil slurry. In embodiments of the invention, at least one glass-forming mono- or di-saccharide, and/or glass-forming polysaccharides, such as maltodextrins and dextrins may be included in the glassy matrix composition by preblending with the glass-forming oligosaccharide matrix component.
In the fortification of foods with calcium, absorption of calcium into the blood stream is substantially enhanced by the glass-forming oligosaccharide matrix material such as fructooligosaccharides and inulin. In addition, medium chain triglycerides (MCT) may be employed as the edible oil component to also substantially enhance the absorption of calcium into the blood. Lactose may also be used as a glass-forming matrix component to also enhance calcium absorption into the blood stream. Fortification of foods such as ready-to-eat cereals and yogurt with at least 100% of the Recommended Daily Allowances (RDA) of calcium is obtained without imparting a chalky, gritty mouthfeel, off-flavors, and undesirable browning or discoloration. Adverse interaction, reaction, or complexing of calcium with proteins or other food components, during storage, or during heating or cooking in the preparation of the food are avoided. In preferred embodiments, the elemental calcium content of the fortification ingredient may be about 15% by weight to about 32% by weight, based upon the total weight of the glass-forming oligofructose matrix component.